On definably proper maps
Volume 233 / 2016
Fundamenta Mathematicae 233 (2016), 1-36
MSC: Primary 03C64; Secondary 55N30.
DOI: 10.4064/fm96-12-2015
Published online: 2 December 2015
Abstract
In this paper we work in o-minimal structures with definable Skolem functions, and show that: (i) a Hausdorff definably compact definable space is definably normal; (ii) a continuous definable map between Hausdorff locally definably compact definable spaces is definably proper if and only if it is a proper morphism in the category of definable spaces. We give several other characterizations of definably proper, including one involving the existence of limits of definable types. We also prove the basic properties of definably proper maps and the invariance of definably proper (and definably compact) in elementary extensions and o-minimal expansions.
